Study the impact of microplastic pollutants on marine algae by novel dielectric spectroscopy method

Microplastics are easy to be dispersed in the ocean due to its small size. Under the action of wind or hydraulic force such as tides, waves, and ocean currents, it can migrate both in and out of the ocean water column. It can also be transported over long distance in the ocean by surface currents. The impact of microplastics on the marine ecological environment is multifaceted. First, due to its small size, it is easily eaten by invertebrates and marine organisms and, then, through the food chain and food web, it is enriched to high-trophic organisms, which in turn affects human health. Secondly, microplastics also hinder the absorption of sunlight by marine algae, affect the photosynthesis of algae, and play a crucial role in the circulation and energy flow of nitrogen, phosphorus and other substances in the marine ecosystem. Therefore, there is an urgent need to develop methodologies to better understand the effects of microplastics on algae. The dielectric spectroscopy method, which can fast and accurately obtain the internal information of the substance, thereby realizing the non-destructive and rapid measurement of the sample. Therefore, this method was increasingly favored by researchers. In this paper, a PCB coaxial probe based on dielectric spectroscopy was designed. Dielectric spectroscopy was used to analyze changes in dielectric constant of marine algae at different concentrations of microplastic pollutants